1. Field of the Invention
This invention relates generally to a furnace configuration by arranging the mechanical and electric units to carry out heating-cooling processes for electronic component manufacturing, food process, or medical sterilization applications. More particularly, this invention relates to a new and improved furnace configuration to simplify the processes for manufacturing electronic component, for food processing, or for carrying out medical sterilization applications while reducing wastes of energy and achieving time-saving required for the processes.
2. Description of the Related Art
The conventional furnaces are still limited by the technical difficulties that linear conveyors are often employed to carry the objects through a furnace to perform several cycles of heating and cooling processes through several chambers or zones. Specifically, the conventional furnaces used in the electronic industry for processing and soldering the Printed Circuit Board (PCB) assemblies are constructed by employing linear conveyors. The object to be heated is placed on the conveyer at the inlet of the furnace and the conveyer then carries the object to move linearly through a series of heating chambers with pre-set temperatures. Some chambers are equipped with heaters and fans to carry out the pre-heating or intensive heating operations while the subsequent chambers are installed with fans to follow with a process to cool down the objects according to the process requirements. In the conventional configuration, there are excessive energy wastes due to heat losses caused by the hot air leaks from the multiple openings in heat chambers to accommodate the entry and exit of the linear conveyers. Also energy is wasted due to the inefficiency of heat utilization as the hot air continuously migrates to the top of the heat chamber while the objects for heating processes are passed through the bottom of the heating chambers. Furthermore, in a batch process, when the cooling and heating processes are performed in a single chamber, the heating and cooling cycles often prolong the manufacturing processes because the processing cycles requires minimum lengths of time for the objects to cool down and pre-heat before a next heating cycle may begin. All these limitations add to the cost and manufacture complexities when a conventional furnace is employed.
U.S. Pat. No. 5,154,338 discloses the heating units arrangement with fan in each chamber to be installed opposite one another above and below the conveyor to constitute as a pair along the line and separated by the partial partition so that all the boards can be carried through these chambers from one end (inlet) to the other end (outlet). Therefore, at least two operators are required to carry out the tasks of heating profile adjustment, board loading as well as unloading, and quality inspection. The heat generated at each chamber cannot be easily recovered and used again by other chambers unless a special and more costly heat recycle designs are implemented to improve the energy recycling. Another limitation of the patented invention is the limited amount of reduction that can be accomplished in reducing the inner gas consumption by installing the necessary partitions as disclosed in this patent. Other drawback of the linear type furnace is the limitation that such furnaces are not suitable for application in offices or laboratories due to the volume occupied by the furnace. Due to the required space, installation of a furnace in a medical laboratory or restaurant for food processes is not feasible even that such furnace would be quite convenient and useful for heat treatments. The patented invention does not resolve the difficulties of inefficiency use of energy, as the main door of the oven has to be opened for each loading-unloading cycle. Consequently, the heat applied in the previous batch operation is lost, so does the inert gas pumped into the chambers of the furnace. The oven has to be heated again for each cycle for a period of time, so does the inert gas too.
For these reasons, there is a need for providing new and improved furnace configurations and techniques of using the furnace for simpler, faster, more energy efficient and more economical methods to carry out heating processes as that required in many different applications. It is desirable that a person of ordinary skill in the art is enabled to design a furnace that is smaller more convenient to operate, more energy efficient, and can be easily adapted into different kinds of operation environments for broader applications.